Portable power-driven chain saws

ABSTRACT

The present portable engine-driven chain saw has a casing for the engine with a side air inlet opening facing a fan-impeller attached to the engine drive shaft for cooling the engine, a cover for said casing opening having a front wall with air inlet openings and sidewalls spacing said cover front wall from said fan-impeller providing an area in which is positioned a perforated strainer plate attached to said drive shaft between said front wall and said fan-impeller for catching impurities such as sawdust, wood chips, pieces of bark or snow coming in with the air and throwing such impurities by centrifugal force through openings in said cover sidewalls away from the operator&#39;&#39;s face.

United States Patent [72] lnventor Gunther l-LW. Dobbertin Ovre Olskroksgatan 28, Goteborg, Sweden [21] Appl. No. 741,189 [22] Filed June 28, 1968 [45] Patented Mar. 2, 1971 [32] Priority June 30, 1967 [3 3 Sweden [31 9898/1967 [54] PORTABLE POWER-DRIVEN CHAIN SAWS 1 Claim, 4 Drawing Figs. [52] US. Cl 123/41.65, 143/32 [51] Int. Cl B27b 17/02 [50] Field ofSearch 143/32; 123/4165, 41.7

[ 56] References Cited UNITED STATES PATENTS 2,747,558 5/1956 Kiekhaefer 123/41.7X

3,252,449 5/1966 Couchmanetal 3,157,211 11/1964 Wiig Primary Examiner-Donald R. Schran Attorney-Linton & Linton ABSTRACT: The present portable engine-driven chain saw has a casing for the engine with a side air inlet opening facing a fan-impeller attached to the engine drive shaft for cooling the engine, a cover for said casing opening having a front wall with air inlet openings and sidewalls spacing said cover front wall from said fan-impeller providing an area in which is positioned a perforated strainer plate attached to said drive shaft between said front wall and said fan-impeller for catching impurities such as sawdust, wood chips, pieces of bark or snow coming in with the air and throwing such impurities by centrifugal force through openings in said cover sidewalls away from the operators face.

' PAIENIED m 2m SHEET 1 (If 2 v INVENTOR GUNTH R HEINRICH WiLHELM DOBBERTIN I ATTORNEYS PATENTEDHARZIHYI 3568848 snmznrz INVENTOR GUNTHERHEINRICH w yusun DOBBERTIN MW ZZI ATTORNEYS space. in winter time, the space between the PORTABLEPOWER-DRIVEN CHAIN SAWS The present invention relates to portable power-driven chain saws of the kind wherein the engine housing is provided with a casing which comprises, at one of those'sides which are substantially parallel with the plane of the saw chain guide bar, a cover for a fan attached to the engine shaft, said cover being provided with air supply openings. 1 v

Previously known chain saws of this type have the drawback that particles which are sucked by the fan intothe space between the fan and the fan, ccvermay accumulate in said fan and the cover will often be filledwith snow. The object of the present invention is to overcome the above-mentioned drawbacks. According to the invention said cover .connects, at that .edge .thereof which is directed downwardly in-the position of use of the saw, to a portion directed towards the, engine housing, said portion being provided with outlet openings for, impurities entering the space between the cover and the fan.

One embodiment of the invention will be described in greater detail herebelow with reference to the accompanying drawings, wherein:

F IG. -l is a partly broken side view of a power-driven chain saw; FIG. 2 is a partly broken view to a'larger scale from below of the fan cover'of the saw shown in FIG. 1;

FlG. 3'is a cross section taken on the line lll-lll in HQ 1; and

FIG. 4 is a longitudinal section taken on the line lV-lV in FIG. 1. r Y

In the drawings, numeral 1 indicates the engine housing of I the saw together with its casing; The engine housing is provided with a handle 2 and a carrying yoke 3. Numeral 4 indicates the guide bar for the saw chain.

The casing of the engine housing 1 includes a cover 5 which is mounted on one end of the engine shaft. The cover 5 is provided with a number of slot-shaped air supply openings 6 and 7. As shown in FIG. 3, the cover 5 which is elongated in the longitudinal direction of the guide bar has a channel-shaped cross section, the openings 6 and 7 being provided in that portion of the cover which forms the bottom of the channel section, whereas that sidewall of the cover which is directed upthe like may be thrown upby the fan intothe face of the operator. At that edge of the cover. 5 which is opposite to the wall 8 and which is thus turned downwardly in the position of use of the saw the-cover connects to a portion 9 which is directed towards the engine housing, said portion 9 forming the second sidewall of the channel-shaped cross section. The wall 9 is provided with openings 10 and 11 through which particles entering the space between the cover 5 and the fan may fall out. There is further provided, at the inner side of the cover 5, a transverse wall 12 which extends from the upper wall 8 to the lower wall 9 and which serves for catching particles of dirt and the like and guiding the same'down towards the openings 10 and 11 in the wall 9.

The wall 9 wherein the outlet openings 10 and 11 are provided need not constitute an integral part of the cover 5 but .may be made in one piece with the-adjacentportion of the engine housing.

As shown in FIGS. 3 and 4, the impeller 13 of the fan is attached to the engine shaft 14 and is provided at the intake side with a shallow cup-shaped perforated strainer plate 15 rotating together with the impeller. In the space between the strainer plate 15 and the inner side of the cover 5 there is further provided, in a mannerknown per se, a starting device 16 of the type which is operated manually by means of a wire.

Particles entering 'the space between the fan and the inner side of the cover 5 through the openin s in the latter will be prevented by the rotating strainer plate rom reaching the impeller, and such particles will instead bounce against the rotat- "therewith, and a casing having an air inlet opening in front of wardly in the position of use of the saw as seen in FIG. 1) and which is indicated at 8 has no air supply openings.

This form of the cover 5 avoids the drawback of the previously known power-driven chain saws that dirt particles and said fan-impeller, and including a cover for said casing air inlet opening having a front wall opposite said fan-impeller and sidewalls connected to said casing and attached to said front wall, forming a space between saidfront wall and said fan-impeller, said cover front wall having air inlet openings, a perforated strainer plate attached to said drive shaft between said fan-impeller and said front wall and arranged to catch impurities in the air coming from said cover front wall inlet openings and conduct such impurities laterally of saidstrainer plate by centrifugal force and said cover sidewalls have openings positioned therein for the passage of such discharged impurities away from the face of an operator of said saw. 

1. In a portable engine-driven chain saw having an engine drive shaft, a fan-impeller provided on said shaft for rotation therewith, and a casing having an air inlet opening in front of said fan-impeller, and including a cover for said casing air inlet opening having a front wall opposite said fan-impeller and sidewalls connected to said casing and attached to said front wall, forming a space between said front wall and said fanimpeller, said cover front wall having air inlet openings, a perforated strainer plate attached to said drive shaft between said fan-impeller and said front wall and arranged to catch impurities in the air coming from said cover front wall inlet openings and conduct such impurities laterally of said strainer plate by centrifugal force and said cover sidewalls have openings positioned therein for the passage of such discharged impurities away from the face of an operator of said saw. 